The Lockheed JetStar (company designations L-329 and L-1329; designatedC-140 in USAF service) is a business jet produced from the early 1960s to the 1970s. The JetStar was the first dedicated business jet to enter service. It was also one of the largest aircraft in the class for many years, seating ten plus two crew. It is distinguishable from other small jets by its four engines, mounted on the rear of the fuselage in a similar layout to the larger Vickers VC10 airliner that first flew several years later, and the "slipper"-style fuel tanks fixed to the wings.

The JetStar originated as a private project within Lockheed, with an eye to winning a USAF requirement that was later dropped due to budget cuts. Lockheed decided to continue the project on their own for the business market.[1]

The first two prototypes were equipped with two Bristol Siddeley Orpheus engines, the first of these, N329J, flying on 4 September 1957. The second of these was also equipped with the wing-mounted "slipper tanks", which was originally to be an option. Lockheed attempted to arrange a contract to produce the Orpheus in the US, but when these negotiations failed they re-engined the second prototype, N329K, with four Pratt & Whitney JT12 in 1959. The slipper tanks were removed and placed on the first prototype, N329J. N329J served as Clarence Johnson's personal transport for some time. The JT12 fit proved successful and was selected for the production versions, the first of which flew in mid 1960.[2] These versions entered commercial service in 1961.

The Dryden C-140 JetStar during testing of advanced propfan designs

An Air Force Communications Service C-140A facilities checking aircraft displayed at the 1963 Paris Air Show

Sixteen JetStars were produced for the United States Air Force. Five C-140A were flight inspection aircraft for the Air Force Communications Service and were used to perform airborne testing of airport navigational aids from 1962 onwards. They began service during the Vietnam War and remained in service until the early 1990s. The "Flight Check" C-140A were a combat-coded aircraft that could be distinguished from the VIP transport version by their distinctive camouflage paint scheme. The last C-140A to be retired was placed on static display at Scott AFB, Illinois.

An additional 11 airframes were designated C-140B, although the first of these predated the C-140As when it was delivered in 1961. The C-140Bs were used to transport personnel by the Military Airlift Command. Six of the aircraft were operated as VIP transports by the 89th Military Airlift Wing at Andrews Air Force Base. These VIP aircraft were designated as VC-140Bs. The VIP transport fleet occasionally served as Air Force One during the 1970s and 1980s. Several other countries, such as Germany and Canada, have used military JetStars as transports for their heads of state, heads of government, and other VIPs.

Noise regulations in the United States and high fuel consumption led to the development of the 731 JetStar, a modification program which added new Garrett AiResearchTFE731turbofan engines and redesigned external fuel tanks to original JetStars. The 731 JetStar modification program was so successful that Lockheed produced 40 new JetStars, designated the JetStar II, from 1976 through 1979. The JetStar IIs were factory-new aircraft with the turbofan engines and revised external fuel tanks. Both 731 JetStars and JetStar IIs have greatly increased range, reduced noise, and better runway performance compared to the original JetStars.

JetStar production totaled 204 aircraft by final delivery in 1978.[3] Most original JetStars have been retired, but many 731 JetStars and JetStar IIs are still flying in various roles, mainly as corporate and private jets.

Lockheed VC-140B. The bare metal on the fin at the trim hinge is easily visible here.

The JetStar has a fairly typical business jet design layout, with a swept wing and a cruciform tail. The wing has a 30° sweepback and features large fuel tanks at about half-span, extending some distance in front and behind the wing. The wings hold 10,000 pounds of fuel, and each slipper tank holds 4,000 pounds of fuel for a total fuel load of 18,000 pounds. The wing also includes leading edge flaps (not slats) along the front of the wing outboard of the tanks (these leading edge flaps reduce the stalling speed by an additional three knots), while double-slotted trailing edge flaps span the entire rear surface inboard of the ailerons. The wing incorporates inflatable rubber deicing boots for the removal of accumulated inflight ice. The horizontal stabilizers are mounted nearly halfway up the tail fin to keep it clear of the jetwash. One feature is that trim is provided by pivoting the entire tail fin, which has a distinctive unpainted area at the base of the fin that is noticeable in most pictures. The Jetstar does not have any tail deicing capability, nor was it required for certification. A speed brake is located on the underside of the fuselage to aid deceleration for landing. The original prototypes used a tricycle landing gear with one wheel per leg, but after an accident in 1962 the nose gear was modified with two tires.[3]

The JetStar is a relatively heavy aircraft for its class, at 44,500 lb (19,278 kg). Maximum cruising speed is Mach 0.8, or 567 mph (912 km/h) at 21,000 ft (6,401 m). Range is typically quoted as 2,500 mi (4,023 km) with a 3,500 lb (1,588 kg) payload. Typically, interiors feature seating for eight with a full-sized lavatory, or a slightly denser arrangement for ten. The JetStar is one of the few aircraft of its class which allow a person to walk upright in the cabin, although to do this the aisle is sunk slightly so that the seats are raised on either side.[4] The windows are relatively large.

The JetStar II is generally similar, with a number of detail changes. The cockpit area has a somewhat more "modern" looking nose and window arrangement, larger engines, and most notably, the fuel tanks are larger and sit with their upper surfaces flush with the wing, rather than being centered on it.

Flight inspection aircraft for the US Air Force, similar to the JetStar I, five built.

C-140B

Passenger, cargo transport aircraft for the US Air Force, similar to the C-140A, five built.

VC-140B

VIP transport aircraft for the US Air Force, similar to the C-140B, six built.

C-140C

Two JetStar 6s were ordered by the United States Navy, originally designated UV-1, but not delivered.

T-40

US military designation for a proposed trainer version of the C-140 for evaluation, not built.

AAI FanStar

Conversion by American Aviation Industries with two General Electric CF34 engines in place of the four JT12 turbojets or TFE731 turbofans which first flew on 5 September 1986.[5] Only one aircraft was converted.